Air conditioning apparatus having subcooling and hot vapor reheat and associated methods

An air conditioning apparatus comprising:

• an evaporator, a condenser, and a compressor for circulating refrigerant through said condenser and said evaporator, said compressor having a refrigerant outlet;
• air handling means for generating an air flow over said evaporator to cool the air flow;
• refrigerant subcool and air reheat means for subcooling refrigerant being delivered to said evaporator and for reheating the air flow downstream from said evaporator;
• a hot vapor heat exchanger, connectable in fluid communication with the refrigerant outlet of said compressor and positioned in the air flow downstream from said evaporator, for further reheating the air flow from said evaporator;
• and
• hot vapor heat exchanger control means for selectively connecting said hot vapor heat exchanger in fluid communication with the refrigerant outlet of said compressor responsive to a sensed condition.

An air conditioning apparatus comprising:

• an evaporator, a condenser, and a compressor for circulating refrigerant through said condenser and said evaporator, said compressor having a refrigerant outlet;
• air handling means for generating an air flow over said evaporator to cool the air flow;
• a hot vapor heat exchanger, connectable in fluid communication with the refrigerant outlet of said compressor and positioned in the air flow downstream from said evaporator, for reheating the air flow from said evaporator;
• a solenoid valve connected in fluid communication with said hot vapor heat exchanger;
• a thermostatic switch operatively connected to said solenoid valve for opening said solenoid valve responsive to a temperature of air downstream from said hot vapor heat exchanger being below a predetermined temperature;
• and
• a differential pressure control valve connected in fluid communication between said compressor and said condenser and across said hot vapor heat exchanger for further controlling reheating by said hot vapor heat exchanger when said solenoid valve is open.

An air conditioning apparatus comprising:

• an evaporator, a condenser, and a compressor for circulating refrigerant through said condenser and said evaporator, said evaporator having a refrigerant inlet, said compressor having a refrigerant outlet;
• air handling means for generating an air flow over said evaporator to cool the air flow and remove moisture therefrom;
• a subcooling heat exchanger, connected in fluid communication with the refrigerant inlet of said evaporator and positioned in the air flow downstream from said evaporator, for subcooling refrigerant being delivered to said evaporator and for reheating the air flow downstream from said evaporator to lower a relative humidity of the air flow;
• a hot vapor heat exchanger, connectable in fluid communication with the refrigerant outlet of said compressor and positioned in the air flow downstream from said evaporator, for further reheating the air flow from said evaporator to further lower the relative humidity of the air flow;
• and
• hot vapor heat exchanger control means for selectively connecting said hot vapor heat exchanger in fluid communication with the refrigerant outlet of said compressor responsive to a sensed condition, said hot vapor heat exchanger control means comprising
• a solenoid valve connected in fluid communication between said hot vapor heat exchanger and the refrigerant outlet of said compressor,
• a switch operatively connected to said solenoid valve for opening said solenoid valve responsive to at least one of a sensed temperature and a humidity of air downstream from said hot vapor heat exchanger, and
• a differential pressure control valve connected in fluid communication between said compressor and said condenser and across said hot vapor heat exchanger for further controlling reheating by said hot vapor heat exchanger when said solenoid valve is open.

An air conditioning apparatus comprising:

• an evaporator, a condenser, and a compressor for circulating refrigerant through said condenser and said evaporator, said evaporator having a refrigerant inlet, said compressor having a refrigerant outlet;
• air handling means for generating an air flow over said evaporator to cool the air flow and remove moisture therefrom;
• a subcooling heat exchanger, connected in fluid communication with the refrigerant inlet of said evaporator and positioned in the air flow downstream from said evaporator, for subcooling refrigerant being delivered to said evaporator and for reheating the air flow downstream from said evaporator to lower a relative humidity of the air flow;
• a hot vapor heat exchanger, connectable in fluid communication with the refrigerant outlet of said compressor and positioned in the air flow downstream from said evaporator, for further reheating the air flow from said evaporator to further lower the relative humidity of the air flow;
• and
• hot vapor heat exchanger control means for selectively connecting said hot vapor heat exchanger in fluid communication with the refrigerant outlet of said compressor responsive to a sensed condition, said hot vapor heat exchanger control means comprising a check valve connected in fluid communication with said hot vapor heat exchanger.

A method for operating an air conditioning apparatus comprising an evaporator, a condenser, and a compressor for circulating refrigerant through the condenser and the evaporator, said method comprising the steps of:

• generating an air flow over the evaporator to cool the air flow;
• subcooling refrigerant being delivered to the evaporator and while reheating the air flow downstream from the evaporator to lower a relative humidity of the air flow;
• and
• selectively connecting a hot vapor heat exchanger in fluid communication with a refrigerant outlet of the compressor and positioned in the air flow downstream from the evaporator for further reheating the air flow from the evaporator to further lower the relative humidity of the air flow.

An air conditioning apparatus comprising:

• an evaporator, a condenser, and a compressor for circulating refrigerant through said condenser and said evaporator, said evaporator having a refrigerant inlet, said compressor having a refrigerant outlet;
• air handling means for generating an air flow over said evaporator to cool the air flow and remove moisture therefrom;
• a subcooling heat exchanger, connected in fluid communication with the refrigerant inlet of said evaporator and positioned in the air flow downstream from said evaporator, for subcooling refrigerant being delivered to said evaporator and for reheating the air flow downstream from said evaporator to lower a relative humidity of the air flow;
• a hot vapor heat exchanger, connectable in fluid communication with the refrigerant outlet of said compressor and positioned in the air flow downstream from said evaporator, for further reheating the air flow from said evaporator to further lower the relative humidity of the air flow;
• and
• condenser pressure control means associated with said condenser for maintaining a desired pressure at an outlet of said condenser.